The air quality was recorded in the "moderate" category in Noida and Faridabad while it was "poor" in Greater Noida, Ghaziabad and Gurgaon, according to data issued by a government agency on Saturday.
Pollutants PM 2.5 and PM 10 also remained high in the air of the five immediate neighbours of Delhi, according to the air quality index (AQI) maintained by the Central Pollution Control Board (CPCB).
According to the index, an AQI between zero and 50 is considered ''good'', 51 and 100 ''satisfactory'', 101 and 200 ''moderate'', 201 and 300 ''poor'', 301 and 400 ''very poor'', and 401 and 500 ''severe''.
The average 24-hour AQI at 4 pm on Saturday was 244 in Ghaziabad, 229 in Greater Noida, 167 in Noida, 145 in Faridabad and 217 in Gurgaon, according to CPCB''s Sameer app.
On Friday it was 263 in Ghaziabad, 240 in Greater Noida, 199 in Noida, 243 in Faridabad and 240 in Gurgaon.
The CPCB states that an AQI in the "poor" category may lead to breathing discomfort to most people on prolonged exposure, while air quality in the "moderate" zone may cause breathing discomfort to the people with lungs, asthma and heart diseases.
The AQI for each city is based on the average value of all monitoring stations there. Ghaziabad, Gurgaon and Noida have four such stations while Greater Noida and Faridabad have two stations each, according to the app.